I made a thread recently where I showed how to apply anti-aliasing in any game running through WINE. Now I'm here to show how to force anisotropic filtering in games, however I think it only works on AMD GPUs. If you know the way to do it on Intel or Nvidia please share. Anyway, it's as simple as adding a single environment variable: RADV_TEX_ANISO=16
If you're new to this you just need to add this as a launch option on steam: RADV_TEX_ANISO=16 %command%
Or if you're using Lutris it's done in the game's system tab, where you can find the environment variable table.
If you're using anything else you basically just have to add RADV_TEX_ANISO=16 before running the command that starts the game.